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<pre><span class="sourceLineNo">001</span><a name="line.1"></a>
<span class="sourceLineNo">002</span>/*<a name="line.2"></a>
<span class="sourceLineNo">003</span> * Copyright (C) 2014 Archie L. Cobbs. All rights reserved.<a name="line.3"></a>
<span class="sourceLineNo">004</span> *<a name="line.4"></a>
<span class="sourceLineNo">005</span> * $Id: ReferenceField.html 842 2015-03-07 18:20:42Z archie.cobbs $<a name="line.5"></a>
<span class="sourceLineNo">006</span> */<a name="line.6"></a>
<span class="sourceLineNo">007</span><a name="line.7"></a>
<span class="sourceLineNo">008</span>package org.jsimpledb.core;<a name="line.8"></a>
<span class="sourceLineNo">009</span><a name="line.9"></a>
<span class="sourceLineNo">010</span>import java.util.Set;<a name="line.10"></a>
<span class="sourceLineNo">011</span>import java.util.SortedSet;<a name="line.11"></a>
<span class="sourceLineNo">012</span><a name="line.12"></a>
<span class="sourceLineNo">013</span>/**<a name="line.13"></a>
<span class="sourceLineNo">014</span> * A field that references another {@link Database} object.<a name="line.14"></a>
<span class="sourceLineNo">015</span> *<a name="line.15"></a>
<span class="sourceLineNo">016</span> * &lt;p&gt;<a name="line.16"></a>
<span class="sourceLineNo">017</span> * Null values sort last.<a name="line.17"></a>
<span class="sourceLineNo">018</span> * &lt;/p&gt;<a name="line.18"></a>
<span class="sourceLineNo">019</span> *<a name="line.19"></a>
<span class="sourceLineNo">020</span> * &lt;p&gt;<a name="line.20"></a>
<span class="sourceLineNo">021</span> * Reference fields are always indexed.<a name="line.21"></a>
<span class="sourceLineNo">022</span> * &lt;/p&gt;<a name="line.22"></a>
<span class="sourceLineNo">023</span> */<a name="line.23"></a>
<span class="sourceLineNo">024</span>public class ReferenceField extends SimpleField&lt;ObjId&gt; {<a name="line.24"></a>
<span class="sourceLineNo">025</span><a name="line.25"></a>
<span class="sourceLineNo">026</span>    final DeleteAction onDelete;<a name="line.26"></a>
<span class="sourceLineNo">027</span>    final boolean cascadeDelete;<a name="line.27"></a>
<span class="sourceLineNo">028</span><a name="line.28"></a>
<span class="sourceLineNo">029</span>    /**<a name="line.29"></a>
<span class="sourceLineNo">030</span>     * Constructor.<a name="line.30"></a>
<span class="sourceLineNo">031</span>     *<a name="line.31"></a>
<span class="sourceLineNo">032</span>     * @param name the name of the field<a name="line.32"></a>
<span class="sourceLineNo">033</span>     * @param storageId field storage ID<a name="line.33"></a>
<span class="sourceLineNo">034</span>     * @param schema schema version<a name="line.34"></a>
<span class="sourceLineNo">035</span>     * @param onDelete deletion behavior<a name="line.35"></a>
<span class="sourceLineNo">036</span>     * @param cascadeDelete whether to cascade deletes<a name="line.36"></a>
<span class="sourceLineNo">037</span>     * @param objectTypes allowed object type storage IDs, or null for no restriction<a name="line.37"></a>
<span class="sourceLineNo">038</span>     * @throws IllegalArgumentException if any parameter is null<a name="line.38"></a>
<span class="sourceLineNo">039</span>     * @throws IllegalArgumentException if {@code name} is invalid<a name="line.39"></a>
<span class="sourceLineNo">040</span>     * @throws IllegalArgumentException if {@code storageId} is invalid<a name="line.40"></a>
<span class="sourceLineNo">041</span>     */<a name="line.41"></a>
<span class="sourceLineNo">042</span>    ReferenceField(String name, int storageId, Schema schema,<a name="line.42"></a>
<span class="sourceLineNo">043</span>      DeleteAction onDelete, boolean cascadeDelete, Set&lt;Integer&gt; objectTypes) {<a name="line.43"></a>
<span class="sourceLineNo">044</span>        super(name, storageId, schema, new ReferenceFieldType(objectTypes), true);<a name="line.44"></a>
<span class="sourceLineNo">045</span>        if (onDelete == null)<a name="line.45"></a>
<span class="sourceLineNo">046</span>            throw new IllegalArgumentException("null onDelete");<a name="line.46"></a>
<span class="sourceLineNo">047</span>        this.onDelete = onDelete;<a name="line.47"></a>
<span class="sourceLineNo">048</span>        this.cascadeDelete = cascadeDelete;<a name="line.48"></a>
<span class="sourceLineNo">049</span>    }<a name="line.49"></a>
<span class="sourceLineNo">050</span><a name="line.50"></a>
<span class="sourceLineNo">051</span>// Public methods<a name="line.51"></a>
<span class="sourceLineNo">052</span><a name="line.52"></a>
<span class="sourceLineNo">053</span>    /**<a name="line.53"></a>
<span class="sourceLineNo">054</span>     * Get the desired behavior when an object referred to by this field is deleted.<a name="line.54"></a>
<span class="sourceLineNo">055</span>     *<a name="line.55"></a>
<span class="sourceLineNo">056</span>     * @return desired behavior when a referenced object is deleted<a name="line.56"></a>
<span class="sourceLineNo">057</span>     */<a name="line.57"></a>
<span class="sourceLineNo">058</span>    public DeleteAction getOnDelete() {<a name="line.58"></a>
<span class="sourceLineNo">059</span>        return this.onDelete;<a name="line.59"></a>
<span class="sourceLineNo">060</span>    }<a name="line.60"></a>
<span class="sourceLineNo">061</span><a name="line.61"></a>
<span class="sourceLineNo">062</span>    /**<a name="line.62"></a>
<span class="sourceLineNo">063</span>     * Determine whether the referred-to object should be deleted when an object containing this field is deleted.<a name="line.63"></a>
<span class="sourceLineNo">064</span>     *<a name="line.64"></a>
<span class="sourceLineNo">065</span>     * @return whether deletion should cascade to the referred-to object<a name="line.65"></a>
<span class="sourceLineNo">066</span>     */<a name="line.66"></a>
<span class="sourceLineNo">067</span>    public boolean isCascadeDelete() {<a name="line.67"></a>
<span class="sourceLineNo">068</span>        return this.cascadeDelete;<a name="line.68"></a>
<span class="sourceLineNo">069</span>    }<a name="line.69"></a>
<span class="sourceLineNo">070</span><a name="line.70"></a>
<span class="sourceLineNo">071</span>    /**<a name="line.71"></a>
<span class="sourceLineNo">072</span>     * Get the object types this field is allowed to reference, if so restricted.<a name="line.72"></a>
<span class="sourceLineNo">073</span>     *<a name="line.73"></a>
<span class="sourceLineNo">074</span>     * @return storage IDs of allowed object types, or null if there is no restriction<a name="line.74"></a>
<span class="sourceLineNo">075</span>     */<a name="line.75"></a>
<span class="sourceLineNo">076</span>    public SortedSet&lt;Integer&gt; getObjectTypes() {<a name="line.76"></a>
<span class="sourceLineNo">077</span>        return ((ReferenceFieldType)this.getFieldType()).getObjectTypes();<a name="line.77"></a>
<span class="sourceLineNo">078</span>    }<a name="line.78"></a>
<span class="sourceLineNo">079</span><a name="line.79"></a>
<span class="sourceLineNo">080</span>    @Override<a name="line.80"></a>
<span class="sourceLineNo">081</span>    public &lt;R&gt; R visit(FieldSwitch&lt;R&gt; target) {<a name="line.81"></a>
<span class="sourceLineNo">082</span>        return target.caseReferenceField(this);<a name="line.82"></a>
<span class="sourceLineNo">083</span>    }<a name="line.83"></a>
<span class="sourceLineNo">084</span><a name="line.84"></a>
<span class="sourceLineNo">085</span>    @Override<a name="line.85"></a>
<span class="sourceLineNo">086</span>    public String toString() {<a name="line.86"></a>
<span class="sourceLineNo">087</span>        return "reference field `" + this.name + "'";<a name="line.87"></a>
<span class="sourceLineNo">088</span>    }<a name="line.88"></a>
<span class="sourceLineNo">089</span><a name="line.89"></a>
<span class="sourceLineNo">090</span>// Non-public methods<a name="line.90"></a>
<span class="sourceLineNo">091</span><a name="line.91"></a>
<span class="sourceLineNo">092</span>    @Override<a name="line.92"></a>
<span class="sourceLineNo">093</span>    ReferenceFieldStorageInfo toStorageInfo() {<a name="line.93"></a>
<span class="sourceLineNo">094</span>        return new ReferenceFieldStorageInfo(this, this.parent != null ? this.parent.storageId : 0);<a name="line.94"></a>
<span class="sourceLineNo">095</span>    }<a name="line.95"></a>
<span class="sourceLineNo">096</span>}<a name="line.96"></a>
<span class="sourceLineNo">097</span><a name="line.97"></a>




























































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